Chinook Music db (100% finished)

A Ruby on rails project containing a music database (an Album model and a Track model). The data comes from the db>seeds.rb file.

Table of contents

• General info
• Technologies
• Setup
• Questions

General info

Made during The Hacking Project course on Week5 Day3.

Technologies

Project is created with

• Ruby on Rails 5.2.3

Setup

First, go to the RoR project folder and type:

bundle install

then

rails c

Questions

Copy/paste the corresponding commands for each question in the console to display the answer.

😊 Easy level

• What is the total number of Album objects contained in the database ?

  Album.count

• Who is the author of the song "White Room"?

  Track.find_by(title: "White Room").artist

• Which song lasts exactly 188133 milliseconds?

  Track.find_by(duration: 188133).title

• Which band released the album "Use Your Illusion II" ?

  Album.find_by(title: "Use Your Illusion II").artist

🤨 Medium level

• How many albums have "Great" in their title?

  Album.where("title like ?", "%great%").count

• eletes all the albums whose name contains "music".

  Album.where("title like ?", "%music%").destroy_all

• How many albums are there written by AC/DC ?

  Album.where(artist: "AC/DC").count

• How many songs last exactly 158589 milliseconds?

  Track.where(duration: 158589).count

😵‍💫 Difficult level

• puts in console all the titles of AC/DC.

  Track.where(artist: "AC/DC").each do |track|
    puts track.title
  end

• puts in console all the titles of the album "Let There Be Rock".

  Track.where(album: "Let There Be Rock").each do |track|
    puts track.title
  end

• Calculate the total price of this album and its total duration.

  price = Track.where(album: "Let There Be Rock").sum(:price).round(2)
  duration = Track.where(album: "Let There Be Rock").sum(:duration)
  puts "#{price}, #{duration}"

• Calculate the cost of the entire "Deep Purple" discography.

  Track.where(artist: "Deep Purple").sum(:price).round(2)

• Modify (via a loop) all the titles of "Eric Clapton" so that they are displayed with "Britney Spears" in artist.

  Track.where(artist: "Eric Clapton").each do |track|
    track.update(artist: 'Britney Spears')
  end